Traditional rigid helmets are used to protect the head of an individual from injury or trauma on a jobsite or while participating in various sports. A traditional helmet generally comprises a rigid outer shell having a layer of padding disposed within an interior of the helmet which is adjacent to and in contact with the head of a wearer. The interior padding of the helmet also serves as a cushion to the wearer in the event of an impact force or load realized on the helmet. Traditional rigid helmets used in athletic activities, such as football helmets, have outer shells which are intended to bare the brunt of an impact load during a collision event. The force that traditional rigid helmets are adapted to bare is much greater than a force necessary to cause an injury, such as a concussion, to the individual wearing the helmet. Thus, while the traditional rigid helmet may be intended to bare a great amount of force without fracture or failure, an individual wearing the helmet could receive considerable injury while the rigid outer shell of the traditional helmet would not indicate that such an impact force has been received. For example, some football helmets are designed to have the rigid outer shell maintain its integrity even upon application of forces up to approximately 11,000 pounds per square inch (“psi”). However, an impact load with a force of 11,000 psi realized on a helmet has the potential to cause significant injury to the individual wearing the helmet. Accordingly, it is desirable to provide a helmet cover to cover the outer shell of a traditional rigid helmet, wherein the helmet cover is capable of indicating when an impact force has exceeded a predetermining impact threshold, where the threshold is set at a force level indicating an impact sufficient enough to cause an injury.